s390.c

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      switch (GET_CODE (code))
        {
	case GTU:	return CC0 | CC1;  /* borrow */
	case LEU:	return CC2 | CC3;  /* no borrow */
	default:
	  abort ();
        }
      break;

    case CCUmode:
      switch (GET_CODE (code))
        {
        case EQ:	return CC0;
        case NE:	return CC1 | CC2 | CC3;
        case LTU:	return CC1;
        case GTU:	return CC2;
        case LEU:	return CC0 | CC1;
        case GEU:	return CC0 | CC2;
	default:
	  abort ();
        }
      break;

    case CCURmode:
      switch (GET_CODE (code))
        {
        case EQ:	return CC0;
        case NE:	return CC2 | CC1 | CC3;
        case LTU:	return CC2;
        case GTU:	return CC1;
        case LEU:	return CC0 | CC2;
        case GEU:	return CC0 | CC1;
	default:
	  abort ();
        }
      break;

    case CCAPmode:
      switch (GET_CODE (code))
        {
        case EQ:	return CC0;
        case NE:	return CC1 | CC2 | CC3;
        case LT:	return CC1 | CC3;
        case GT:	return CC2;
        case LE:	return CC0 | CC1 | CC3;
        case GE:	return CC0 | CC2;
	default:
	  abort ();
        }
      break;

    case CCANmode:
      switch (GET_CODE (code))
        {
        case EQ:	return CC0;
        case NE:	return CC1 | CC2 | CC3;
        case LT:	return CC1;
        case GT:	return CC2 | CC3;
        case LE:	return CC0 | CC1;
        case GE:	return CC0 | CC2 | CC3;
	default:
	  abort ();
        }
      break;

    case CCSmode:
      switch (GET_CODE (code))
        {
        case EQ:	return CC0;
        case NE:	return CC1 | CC2 | CC3;
        case LT:	return CC1;
        case GT:	return CC2;
        case LE:	return CC0 | CC1;
        case GE:	return CC0 | CC2;
	case UNORDERED:	return CC3;
	case ORDERED:	return CC0 | CC1 | CC2;
	case UNEQ:	return CC0 | CC3;
        case UNLT:	return CC1 | CC3;
        case UNGT:	return CC2 | CC3;
        case UNLE:	return CC0 | CC1 | CC3;
        case UNGE:	return CC0 | CC2 | CC3;
	case LTGT:	return CC1 | CC2;
	default:
	  abort ();
        }
      break;

    case CCSRmode:
      switch (GET_CODE (code))
        {
        case EQ:	return CC0;
        case NE:	return CC2 | CC1 | CC3;
        case LT:	return CC2;
        case GT:	return CC1;
        case LE:	return CC0 | CC2;
        case GE:	return CC0 | CC1;
	case UNORDERED:	return CC3;
	case ORDERED:	return CC0 | CC2 | CC1;
	case UNEQ:	return CC0 | CC3;
        case UNLT:	return CC2 | CC3;
        case UNGT:	return CC1 | CC3;
        case UNLE:	return CC0 | CC2 | CC3;
        case UNGE:	return CC0 | CC1 | CC3;
	case LTGT:	return CC2 | CC1;
	default:
	  abort ();
        }
      break;

    default:
      abort ();
    }
}

/* If INV is false, return assembler mnemonic string to implement 
   a branch specified by CODE.  If INV is true, return mnemonic 
   for the corresponding inverted branch.  */

static const char *
s390_branch_condition_mnemonic (code, inv)
     rtx code;
     int inv;
{
  static const char *const mnemonic[16] =
    {
      NULL, "o", "h", "nle",
      "l", "nhe", "lh", "ne",
      "e", "nlh", "he", "nl",
      "le", "nh", "no", NULL
    };

  int mask = s390_branch_condition_mask (code);

  if (inv)
    mask ^= 15;

  if (mask < 1 || mask > 14)
    abort ();

  return mnemonic[mask];
}

/* If OP is an integer constant of mode MODE with exactly one
   HImode subpart unequal to DEF, return the number of that 
   subpart.  As a special case, all HImode subparts of OP are
   equal to DEF, return zero.  Otherwise, return -1.  */

int
s390_single_hi (op, mode, def)
     rtx op;
     enum machine_mode mode;
     int def;
{
  if (GET_CODE (op) == CONST_INT)
    {
      unsigned HOST_WIDE_INT value = 0;
      int n_parts = GET_MODE_SIZE (mode) / 2;
      int i, part = -1;

      for (i = 0; i < n_parts; i++)
        {
          if (i == 0)
            value = (unsigned HOST_WIDE_INT) INTVAL (op);
          else
            value >>= 16;

          if ((value & 0xffff) != (unsigned)(def & 0xffff))
            {
              if (part != -1)
                return -1;
              else
                part = i;
            }
        }

      return part == -1 ? 0 : (n_parts - 1 - part);
    }

  else if (GET_CODE (op) == CONST_DOUBLE
           && GET_MODE (op) == VOIDmode)
    {
      unsigned HOST_WIDE_INT value = 0;
      int n_parts = GET_MODE_SIZE (mode) / 2;
      int i, part = -1;

      for (i = 0; i < n_parts; i++)
        {
          if (i == 0)
            value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_LOW (op);
          else if (i == HOST_BITS_PER_WIDE_INT / 16)
            value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_HIGH (op);
          else
            value >>= 16;

          if ((value & 0xffff) != (unsigned)(def & 0xffff))
            {
              if (part != -1)
                return -1;
              else
                part = i;
            }
        }

      return part == -1 ? 0 : (n_parts - 1 - part);
    }

  return -1;      
}

/* Extract the HImode part number PART from integer 
   constant OP of mode MODE.  */

int
s390_extract_hi (op, mode, part)
    rtx op;
    enum machine_mode mode;
    int part;
{
  int n_parts = GET_MODE_SIZE (mode) / 2;
  if (part < 0 || part >= n_parts)
    abort();
  else
    part = n_parts - 1 - part;

  if (GET_CODE (op) == CONST_INT)
    {
      unsigned HOST_WIDE_INT value = (unsigned HOST_WIDE_INT) INTVAL (op);
      return ((value >> (16 * part)) & 0xffff);
    }
  else if (GET_CODE (op) == CONST_DOUBLE
           && GET_MODE (op) == VOIDmode)
    {
      unsigned HOST_WIDE_INT value;
      if (part < HOST_BITS_PER_WIDE_INT / 16)
        value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_LOW (op);
      else
        value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_HIGH (op),
        part -= HOST_BITS_PER_WIDE_INT / 16;

      return ((value >> (16 * part)) & 0xffff); 
    }

  abort ();
}

/* If OP is an integer constant of mode MODE with exactly one
   QImode subpart unequal to DEF, return the number of that 
   subpart.  As a special case, all QImode subparts of OP are
   equal to DEF, return zero.  Otherwise, return -1.  */

int
s390_single_qi (op, mode, def)
     rtx op;
     enum machine_mode mode;
     int def;
{
  if (GET_CODE (op) == CONST_INT)
    {
      unsigned HOST_WIDE_INT value = 0;
      int n_parts = GET_MODE_SIZE (mode);
      int i, part = -1;

      for (i = 0; i < n_parts; i++)
        {
          if (i == 0)
            value = (unsigned HOST_WIDE_INT) INTVAL (op);
          else
            value >>= 8;

          if ((value & 0xff) != (unsigned)(def & 0xff))
            {
              if (part != -1)
                return -1;
              else
                part = i;
            }
        }

      return part == -1 ? 0 : (n_parts - 1 - part);
    }

  else if (GET_CODE (op) == CONST_DOUBLE
           && GET_MODE (op) == VOIDmode)
    {
      unsigned HOST_WIDE_INT value = 0;
      int n_parts = GET_MODE_SIZE (mode);
      int i, part = -1;

      for (i = 0; i < n_parts; i++)
        {
          if (i == 0)
            value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_LOW (op);
          else if (i == HOST_BITS_PER_WIDE_INT / 8)
            value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_HIGH (op);
          else
            value >>= 8;

          if ((value & 0xff) != (unsigned)(def & 0xff))
            {
              if (part != -1)
                return -1;
              else
                part = i;
            }
        }

      return part == -1 ? 0 : (n_parts - 1 - part);
    }

  return -1;      
}

/* Extract the QImode part number PART from integer 
   constant OP of mode MODE.  */

int
s390_extract_qi (op, mode, part)
    rtx op;
    enum machine_mode mode;
    int part;
{
  int n_parts = GET_MODE_SIZE (mode);
  if (part < 0 || part >= n_parts)
    abort();
  else
    part = n_parts - 1 - part;

  if (GET_CODE (op) == CONST_INT)
    {
      unsigned HOST_WIDE_INT value = (unsigned HOST_WIDE_INT) INTVAL (op);
      return ((value >> (8 * part)) & 0xff);
    }
  else if (GET_CODE (op) == CONST_DOUBLE
           && GET_MODE (op) == VOIDmode)
    {
      unsigned HOST_WIDE_INT value;
      if (part < HOST_BITS_PER_WIDE_INT / 8)
        value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_LOW (op);
      else
        value = (unsigned HOST_WIDE_INT) CONST_DOUBLE_HIGH (op),
        part -= HOST_BITS_PER_WIDE_INT / 8;

      return ((value >> (8 * part)) & 0xff); 
    }

  abort ();
}

/* Check whether we can (and want to) split a double-word 
   move in mode MODE from SRC to DST into two single-word 
   moves, moving the subword FIRST_SUBWORD first.  */

bool
s390_split_ok_p (dst, src, mode, first_subword)
     rtx dst;
     rtx src;
     enum machine_mode mode;
     int first_subword;
{
  /* Floating point registers cannot be split.  */
  if (FP_REG_P (src) || FP_REG_P (dst))
    return false;

  /* We don't need to split if operands are directly accessable.  */
  if (s_operand (src, mode) || s_operand (dst, mode))
    return false;

  /* Non-offsettable memory references cannot be split.  */
  if ((GET_CODE (src) == MEM && !offsettable_memref_p (src))
      || (GET_CODE (dst) == MEM && !offsettable_memref_p (dst)))
    return false;

  /* Moving the first subword must not clobber a register
     needed to move the second subword.  */
  if (register_operand (dst, mode))
    {
      rtx subreg = operand_subword (dst, first_subword, 0, mode);
      if (reg_overlap_mentioned_p (subreg, src))
        return false;
    }

  return true;
}


/* Change optimizations to be performed, depending on the 
   optimization level.

   LEVEL is the optimization level specified; 2 if `-O2' is
   specified, 1 if `-O' is specified, and 0 if neither is specified.

   SIZE is nonzero if `-Os' is specified and zero otherwise.  */

void
optimization_options (level, size)
     int level ATTRIBUTE_UNUSED;
     int size ATTRIBUTE_UNUSED;
{
  /* ??? There are apparently still problems with -fcaller-saves.  */
  flag_caller_saves = 0;

  /* By default, always emit DWARF-2 unwind info.  This allows debugging
     without maintaining a stack frame back-chain.  */
  flag_asynchronous_unwind_tables = 1;
}

void
override_options ()
{
  /* Acquire a unique set number for our register saves and restores.  */
  s390_sr_alias_set = new_alias_set ();

  /* Set up function hooks.  */
  init_machine_status = s390_init_machine_status;
}

/* Map for smallest class containing reg regno.  */

const enum reg_class regclass_map[FIRST_PSEUDO_REGISTER] =
{ GENERAL_REGS, ADDR_REGS, ADDR_REGS, ADDR_REGS,
  ADDR_REGS,    ADDR_REGS, ADDR_REGS, ADDR_REGS,
  ADDR_REGS,    ADDR_REGS, ADDR_REGS, ADDR_REGS,
  ADDR_REGS,    ADDR_REGS, ADDR_REGS, ADDR_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  ADDR_REGS,    NO_REGS,   ADDR_REGS 
};


/* Return true if OP a (const_int 0) operand.
   OP is the current operation.
   MODE is the current operation mode.  */
 
int
const0_operand (op, mode)
     register rtx op;
     enum machine_mode mode;
{
  return op == CONST0_RTX (mode);
}

/* Return true if OP is constant.
   OP is the current operation.
   MODE is the current operation mode.  */

int
consttable_operand (op, mode)
     rtx op;
     enum machine_mode mode ATTRIBUTE_UNUSED;
{
  return CONSTANT_P (op);
}

/* Return true if the mode of operand OP matches MODE.
   If MODE is set to VOIDmode, set it to the mode of OP.  */ 

static int
check_mode (op, mode)
     register rtx op;
     enum machine_mode *mode;
{
  if (*mode == VOIDmode)
      *mode = GET_MODE (op);
  else
  {
    if (GET_MODE (op) != VOIDmode && GET_MODE (op) != *mode)
       return 0;
  }
  return 1;
}

/* Return true if OP a valid operand for the LARL instruction.
   OP is the current operation.
   MODE is the current operation mode.  */

int
larl_operand (op, mode)
     register rtx op;
     enum machine_mode mode;
{
  if (! check_mode (op, &mode))
    return 0;

  /* Allow labels and local symbols.  */
  if (GET_CODE (op) == LABEL_REF)
    return 1;